Slide closure for receptacle for molten metals

ABSTRACT

A slide valve for a steel ladle has a removable housing supporting a refractory orifice plate and a pivotally mounted removable cover plate supporting a refractory slide plate. Two spaced seals may be provided between the housing and the ladle.

United States Patent [191 Meier Sept. 25, 1973 SLIDE CLOSURE FORRECEPTACLE FOR MOLTEN METALS [52] US. Cl. 222/533, 222/561 [51] Int. Cl822d 37/00 [58] Field of Search 222/561, 559, DIG. 7,

222/DIG. 17, DIG. 18, 533, 537; 277/234 3,344,965 lO/l967 Kerin ZZZ/DIG.17 3,480,186 11/1969 Groski 222/DlG. 7

2,729,483 1/1956 Victor 277/234 857,134 4/1906 Wilcox 277/234 X PrimaryExaminerRobert B. Reeves Assistant ExaminerDavid A. ScherbelAttorney-Brumbaugh, Graves, Donohue & Raymond 5 7 ABSTRACT A slide valvefor a steel ladle has a removable housing supporting a refractoryorifice plate and a pivotally mounted removable cover plate supporting arefractory slide plate. Two spaced seals may be provided between [56]References Cited the housing and the ladle.

UNITED STATES PATENTS 3,454,201 7/1969 Fichera 222/DIG. 7 7 Claims, 7Drawing Figures .sF/6.7- I

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I ERA/s7" MEIER BY his Arromvzrs SLIDE CLOSURE FOR RECEPTACLE FOR MOLTENMETALS BACKGROUND OF THE INVENTION This invention relates to a slidevalve for the outlet orifice of a container for molten metal,specifically a steel ladle, having an orifice plate fixedly supportedwithin a slide housing that can be attached to the container, and anapertured slide plate which is movable and fits tightly against theorifice plate.

In slide valves proposed heretofore, the housing is permanently attachedto the jacket of the ladle. As a result, the orifice plate, which isfixed in the housing with mortar, is also permanently connected with therefractory lining of the ladle by means of the mortar. In addition, thehousing cover is screwed on tightly so as to press the movable slideplate against the orifice plate in order to assure a tight fit. Thedisadvantages of this design become apparent from the frequent necessityfor a change of worn parts of the slide valve, specifically the orificeplate and the slide plate. In order to change the parts, the casingcover and the slide plate are first removed and then the orifice platemust be broken away from the hot ladle by assiduous work. This isfollowed by affixing a new orifice plate on the ladle, treatment andcleaning of the slide surfaces by means of graphite or molykote, themounting of a new slide plate, the assembly of the casing cover,coupling of the drive for the slide and the tightening of the checkscrews. During this operation, which usually takes more than an hour,the casting ladle is idle. To all this must be added another, veryimportant disadvantage, namely, that the cover of the casing whichpresses the slide plate against the orifice plate, must not be tighteneduntil the mortar with which the new orifice plate is mounted has becomecompletely dry so that the contact pressure of the cover encounters asafe support. Apart from the fact that the setting of the mortar takesquite some time, it has been found to be a disadvantage that it isdifficult to establish whether or not the mortar is set. In general,this method of assembly of the slide valve is greatly subject to humanerrors even if only the worn parts have to be replaced.

Irregularities occurring in this manner, for example, in the assembly ofthe orifice plate, have an effect on the sliding surfaces between theorifice plate and the slide plate, upon which the tightness andcontrollability of the slide valve principally depend.

It is a purpose of the present invention to provide a new and improvedslide valve of the type mentioned above, whereby control of the parts ofthe valve and their flawless assembly is substantially eased incomparison with the known constructions, and whereby the influencethereon of human factors is substantially eliminated.

SUMMARY OF THE INVENTION This is attained in accordance with theinvention by providing a slide valve having four prefabricated elementswhich can be assembled and disassembled without mortar, namely, a rigidslide housing, a fixed plate assembly, including a refractory orificeplate mounted in a metal frame which fits and can be inserted into theslide housing, a second, movable, plate assembly, including a refractoryslide plate mounted in a metal support with a discharge nozzle below theslide plate, and a metal cover which can be screwed to the slidehousing, whereby the contact pressures, on the one hand, between theslide housingand the ladle bottom, and on the other hand, between thetwo plate assemblies are independent of one another.

Preferably, the slide housing is hinged to the container and can pivotin the manner of a gate that can be locked in closed position and can beattached and removed in the open position.

The new construction facilitates replacement of the slide valve within afew minutes, and, moreover, it provides the certainty that the slideplate engages the orifice plate in the desired manner, since preliminaryassembly of the slide valve can be carried out without disturbance andwith utmost care, away from the operating area of the casting ladle, ona work table. A further advantage of this design, and especially of thepivotable arrangement, may be found in the possibility of inspecting theinner parts and mortar joints, and of the ability to come close to therefractory lining of the casting ladle in the area of its discharge, forexample, the discharge drain or nozzle, or a gas sink.

Slide valves have become known wherein the orifice plate and the slideplate are assembled in the slide housing and this aggregate is thenpermanently attached to the jacket of the casting ladle. However, it wasnot recognized that such a construction can be used only under veryspecial conditions. Therefore, these proposed devices did not yield anysatisfactory results, especially for large steel casting ladles;

In contrast to the valves for gases or liquids employed in other fields,a slide valve for molten metals specifically steel, in contrast to thoseused in cold assembly, must withstand a very strong radial temperaturefield pattern which is generated in the refractory portions throughwhich the molten metal flows during operation. This has two far-reachingconsequences: the portions under the influence of the thermal expansion,which varies with time and location, change their original geometricshape, whereby thermal stresses which are variable in place and time aresuperimposed on the basic mechanical stresses. Thus, withoutcompensation, for example, the originally precisely ground sealingsurfaces of the valve would assume a convex shape during operation andwould thereby lose their tightness of engagement.

Now it has been found that the only possible compensation for suchdeformation consists in the application of elastic deformation duringoperations of the parts forming the sealing and sliding surfaces, andthat this is possible only if such parts consist of plates which arecomparatively thin in relation to their extension. The preferable ratioof length to thickness ranges from 5:1 to 10:1. As a result of thegeneration of a variable temperature field pattern during operation, itwas furthermore found to be essential that three force'couples beobtained as independently as possible, namely between the cover of thehousing and the slide housing, between the slide housing and the bottomof the ladle, and between the orifice plate and the discharge nozzle.Only in this case can one ensure that, in a prefabricated andprearranged structural assembly, such as the slide valve in accordancewith the invention, the superimposed thermal stresses will not add tothe basic mechanical stresses in an uncontrollable and dangerous manneror cause relative motion of the parts endangering the safety ofoperation.

Finally, it has been found that the tightness of the joint between theslide valve and the ladle and the discharge duct therein, respectively,can be guaranteed for the construction in accordance with the inventionif the position of the orifice plate in relation to the discharge ductsleeve is predetermined geometrically and cannot be modified either bythe fastening of the housing to the ladle or by the tightening orloosening of the cover of the housing. This is especially valuable forthe desired application of a dry mortar-free joint between the slidehousing and the ladle and the orifice plate and the discharge ductsleeve, respectively, namely, by means of a refractory felt ring betweenthe adjacent refractory parts and, if desired, an additionalcopperasbestos seal between the contiguous metal parts.

Under the described conditions, the felt ring can be dimensioned for ajoint of known and given width in such a manner that its elasticproperties, which are present in spite of the high temperature, serve toabsorb safely the expansions occurring during operation.

A further instability factor is excluded in that, due to prefabricationof the plate assembly, only geometrically stable, fixed andautomatically fitting elements are assembled. If these plate assembliesare prefabricated in a manner whereby the refractory plates are fixed intheir supports or frames by mortar, the assemblies are stabilized priorto assembly of the slide plate valve by sufficient drying and setting ofthe mortar.

Even though mounting on the ladle of the completely assembled slidevalve is preferred, the construction in accordance with the inventionoffers the advantage that successive assembly of the individual elementsin a slide housing already mounted on the ladle is possible withoutdifficulty. The same also applies for disassembly. This flexibility hasmany practical advantages, for example, in the event of a quick changeof individual parts or for inspection of any wear which might haveoccurred after the ladle has been emptied.

BRIEF DESCRIPTION OF THE DRAWINGS A typical embodiment of the inventionis described hereinafter with reference to the drawings, wherein:

FIG. 1 is a view in vertical cross-section illustrating a representativeslide valve according to the invention, illustrating the pivotalmounting of the slide housing;

FIG. 2 is a cross-sectional view through the slide valve of FIG. 1, withthe sectional plane turned by 90;

FIG. 3 is a bottom view of the slide valve shown in FIGS. 1 and 2;

FIG. 4 is a side view of the slide housing;

FIG. 5 is a view showing the slide valve on a casting ladle inpivoted-out position;

FIG. 6 is a bottom view of the slide valve support frame attached to thebottom of a casting ladle with the slide valve removed; and

FIG. 7 is an enlarged view in cross-section showing a detail of thesectional view shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The slide valve illustrated inthe drawings is attached to the metal jacket 1 of a container for moltenmetal, such as a casting ladle. Only the refractory lining of thecasting ladle in the area of the discharge orifice, consisting of acrucible stand 2 and a sleeve 3 are otherwise shown in FIGS. 1 and 2.The slide valve comprises a frame 4 fixed to the casting ladle jacket 1and a slide housing 5 pivotably hinged on the frame. In the exampleshown, the swivel axis consists of two joint pins 6 mounted in the samedirection on frame 4, which pins engage the perforated side bars 7 ofthe slide housing 5. In order to firmly lock the slide housing 5 on theframe 4, there are provided two grooved bolts 8 (FIGS. 4 and 5) whichproject from the frame and into the grooves of which bolts wedges 9(FIG. '3) can be driven, which wedges retain two perforated sidebars 10placed on the bolts 8 when the slide housing 5 is in closed position.

The slide housing contains the essential operating elements of the slidevalve, namely, a stationary plate 1 1 having an orifice and a movableplate 12 having an aperture which cooperates with the orifice of theplate 1 1 for the purpose of closing the valve. While the orifice plate11 is mortared into a support frame 13 which is centered in the slidehousing 5, the sliding plate 12 is supported in a cast iron supportmember 14 having a nozzle or spout 15, which support also accommodates adischarge sleeve 16 below the orifice in the sliding plate 12. Thesupport member 14 rests on the guides 17 of a cover plate 18 which isprovided with an opening so that the spout 15 can be displacedlongitudinally. For the sake of simplicity, only the operating rod 19provided with a hammer head is shown of a hydraulic drive which is usedfor displacement of the support member 14 and the slide plate 12. Theoperating rod 19 engages a correspondingly shaped recess 20 (FIG. 5) inthe support member 14. The cover plate 18 is locked in place by means ofsix eye bolts 21 (FIGS. 2 and 3) provided with cup springs 22.

In order for the slide housing 5, together with all elements it containsto be removed from the joint pins 6 after the wedges 9 have beenloosened, two suspension straps 23 are provided by means of which theslide housing can be suspended on a crane, as shown in FIG. 5.

FIG. 7 illustrates details of the seal between the elements of the slideplate and the ladle. During preliminary assembly, the plate aggregateconsisting of the support frame 13 and the orifice plate 11 mortaredinto it is inserted into the slide housing 5 after the mortar has driedand set, and it is fastened there by means of several bolts 25. Sealingbetween the sleeve 3 and the orifice plate 11 is obtained by arefractory felt ring 26, consisting, for example, of Cerafelt or thelike, which applies itself around the neck of the orifice plate 1 1 andis, therefore, not exposed to direct attack by the molten metal. Acopper-asbestos seal 27 may be provided between the upper plate of theslide housing 5 and the metal jacket of the container 1. This produces aring shaped space which is sealed towards the outside and from which aninert gas, for example argon, can be delivered under pressure into theoutlet of the ladle containing the melt. Both seals can be removedquickly and safely when the slide housing is disassembled.

The replacement of the slide plate of the design described above islimited to the few manipulations required for releasing and lifting offof the old slide housing and suspending and fastening of the new slidehousing. This requires less than 15 minutes. Examination of the interiormortar joints and parts becomes likewise extremely simple in thattowards such end, the slide housing need only to be pivoted away intothe position indicated in dots and clashes in FIG. 1.

I claim:

l. A closure for the outlet orifice of a container for molten metalcomprising a housing removably attached to a container for molten metal,a joint lying between the housing and the container which contains anelastic refractory sealer, a refractory orifice plate fixed in positionwithin the housing having an orifice for discharge of molten metal, arefractory slide plate movably supported within the housing in slidingengagement with the orifice plate, a metal frame removably mounted inthe housing supporting the orifice plate, a metal support for the slideplate, a refractory discharge sleeve below the slide plate, and a metalcover plate removably supported on the housing, wherein the housing ispivotally attached to the container in the manner of a gate andincluding means for removably retaining the housing at its pivot joint,whereby the contact pressures between the housing and the container andbetween the orifice plate and the slide plate are independent of eachother.

2. Slide closure in accordance with claim 1, including suspension strapsmounted on the housing to support the housing duing removal from thecontainer.

3. Slide closure in accordance with claim 2, including mounting meansfor removably supporting the housing and the orifice plate therein infixed and predetermined position with respect to the container.

4. Slide closure in accordance with claim 3, including refractory feltmeans forming a seal between the orifice plate and the container.

5. Slide closure in accordance with claim 4, including an upwardprojection surrounding the orifice in the orifice plate and wherein therefractory felt means surrounds the upward projection.

6. Slide closure in accordance with claim 3, including copper-asbestosseal means between thehousing and the container.

7. In a slide closure in accordance with claim 1, a plate assemblycomprising a metal support frame having the refractory orifice platemortared into the frame so that the support surfaces of the metal frameare parallel to the surface of the orifice plate which-engages the slideplate and are separated therefrom by a predetermined distance.

1. A closure for the outlet orifice of a container for molten metalcomprising a housing removably attached to a container for molten metal,a joint lying between the housing and the container which contains anelastic refractory sealer, a refractory orifice plate fixed in positionwithin the housing having an orifice for discharge of molten metal, arefractory slide plate movably supported within the housing in slidingengagement with the orifice plate, a metal frame removably mounted inthe housing supporting the orifice plate, a metal support for the slideplate, a refractory discharge sleeve below the slide plate, and a metalcover plate removably supported on the housing, wherein the housing ispivotally attached to the container in the manner of a gate andincluding means for removably retaining the housing at its pivot joint,whereby the contact pressures between the housing and the container andbetween the orifice plate and the slide plate are independent of eachother.
 2. Slide closure in accordance with claim 1, including suspensionstraps mounted on the housing to support the housing duing removal fromthe container.
 3. Slide closure in accordance with claim 2, includingmounting means for removably supporting the housing and the orificeplate therein in fixed and predetermined position with respect to thecontainer.
 4. Slide closure in accordance with claim 3, includingrefractory felt means forming a seal between the orifice plate and thecontainEr.
 5. Slide closure in accordance with claim 4, including anupward projection surrounding the orifice in the orifice plate andwherein the refractory felt means surrounds the upward projection. 6.Slide closure in accordance with claim 3, including copper-asbestos sealmeans between the housing and the container.
 7. In a slide closure inaccordance with claim 1, a plate assembly comprising a metal supportframe having the refractory orifice plate mortared into the frame sothat the support surfaces of the metal frame are parallel to the surfaceof the orifice plate which engages the slide plate and are separatedtherefrom by a predetermined distance.